Thiophene-3-isonitriles

ABSTRACT

Thiophene-3-isonitriles of the formula IN WHICH R1 is hydrogen, alkyl, carbalkoxy, cyano or phenyl, R2 is hydrogen, alkyl, alkoxy, carbalkoxy, cyano or phenyl, R3 is hydrogen, alkyl, carbalkoxy or phenyl, or R2 and R3 together represent an alkylene chain, are disclosed as having antimycotic and antibacterial properties.

United States Patent Rippel et al.

[54] THIOPHENE-B-ISONITRILES [72] Inventors: Robert Rippel; Walter Dittmar, both of Hofheim/Taunus; Manfred Schorr, Frankfurt/Main, all of Germany [73] Assignee: Farbwerke Hoechst Aktiengesellschaft, Frankfurt/Main, Germany [22] Filed: Sept. 5, 1969 [21] Appl. No.: 855,726

[30] Foreign Application Priority Data Sept. 23, 1968 Germany ..P 17 93 471.3

[52] US. Cl......260/332.2 C, 260/329 F,260/329 R, 260/329 S, 260/3322 R, 260/3323 R,

1451 Aug. 29, 1972 3,102,841 9/1963 Vecchietal ..167/30 OTHER PUBLICATIONS Smith, Open-Chain Nitrogen Compounds, Vol. I (Benjamin, N.Y., 1965), p. 228 229.

Ugivet al., (II) Angew. Chem. 77(1), P. 502 (1965).

Primary Examinerl-lenry R. Jiles Attorney-Curtis, Morris & Safford [57] ABSTRACT 'I'hiophene-3-isonitriles of the formula R N C R1 1 in which R, is hydrogen, alkyl, carbalkoxy, cyano or I phenyl, R is hydrogen, alkyl, alkoxy, carbalkoxy, cyano or phenyl, R is hydrogen, alkyl, carbalkoxy or phenyl, or R and R together represent an alkylene chain, are disclosed as having antimycotic and antibacterial properties.

5 Claims, No Drawings THIOPHENE-3-ISONITRILES R NC R1 H-R1 S in which R is hydrogen, alkyl having one to six carbon atoms, carbalkoxy having one to four carbon atoms in the alkoxy group, cyano or phenyl,

R is hydrogen, alkyl or alkoxy having one to six carbon atoms, carbalkoxy having one to four carbon atoms in the alkoxy group, cyano or phenyl,

R is hydrogen, alkyl having one to six carbon atoms, carbalkoxy having one to four carbon atoms in the alkoxy group, or phenyl and R and R together represent alkylene having three to four ring members.

This invention relates furthermore to a process for the manufacture of the above specified compounds.

a. The compounds of the invention may be prepared R NH-CHO R31 [R S in which R R and R have the meaning given above, or hydrogen sulfide from the corresponding thioformamides.

As compounds capable of splitting off water or hydrogen sulfide there may be used benzeneor toluenesulfochloride in the presence of anhydrous bases, for example pyridine or quinoline. Water may also be split off by means of phosphorus halides, phosphoroxy halides, phosphorus pentoxide, cyanochloride, cyanobromide, cyanuric acid chloride, generally acylating agents. Suitable bases are, for example, pyridine, potassium tert.-butylate or potassium carbonate. The reaction may also be carried out using phosgene in the presence of tertiary amines such as trimethylamine, triethylamine, tributylamine, N,N- dimethylcyclohexylamine, N,N-diethylamine, pyridine or quinoline. The reactions may be carried out in a homogeneous or heterogeneous phase. The solvents used for the manufacture in the homogeneous phase are inert organic solvents, such as hydrocarbons, halohydrocarbons, ethers, esters, and tertiary amines, for example petrol ether, benzene, methylene chloride, chloroform, tetrahydrofurane, ethyl acetate, monoor dichlorobenzenes, triethylamine and pyridine. If the N- thienyl-formamidine is insoluble, the reaction may also be carried out in a heterogeneous phase by suspending the N-thienyl-formamide in one of the above-mentioned solvents and a base under vigorous stirring and introducing dropwise the compound splitting off water or passing it through the suspension in gaseous form.

The reactions are generally carried out at a temperature in the range of from -20 to +40 C. The product is worked up by adding ammonia or water, separating the organic solvent from the precipitated ammonium chloride or from the amine hydrochloride solution and, after elimination of the solvent by distillation, purifying the crude isonitrile by recrystallization, distillation or chromatography.

The N-thienyl-formamides used as starting materials may be prepared either by heating the corresponding aminothiophenes for 2 to hours at 75 100 C with 2 to 10 times the amount of 85 to 100 percent formic acid, or by contacting the aminothiophenes with a mixture of formic acid and acetic acid anhydride at room temperature. The aminothiophenes may be obtained in known manner according to the processes disclosed in German Pat. Nos. 1,055,007, 1,088,507 and 1,083,830 or by the method of Cheney and Piening (J. Am. Chem. Soc. 67, p. 729, 731 (1945)).

b. The thiophene-3-isonitriles of formula I may also be prepared by reacting thienyl-3-amines with chloroform and strong bases in the manner known for analogous cases. The bases used may, for example, be ethanolic potassium hydroxide solution, solid alkali metal hydroxide or potassium tert.-butylate. Thienyl-3-isonitriles may likewise be obtained 0. by reducing corresponding thienyl-3-isocyanates with the aid of triethylphosphite, or d. by desulfurizing thienyl-3-isothiocyanates with tertiary phosphines, or e. finally by dehalogenating thienyl-3-isonitrilo-dihalides by means of tertiary phosphines. As tertiary phosphines suitable for the above reactions there may be used, for example, triethyl-, tributyltriphenyl-, trichlorphenyl-, diethylbutylor diethylphenylphosphine.

Owing to their excellent antimycotic and antibacterial properties as well as their low toxicity, the products of the invention may be used in human and veterinary therapy for combating local bacterial and fungal infections. For example, dermatomycoses caused by skin fungi and budding fungi, such as trichophytone, microsporum and epidermophyte species as well as Candida albicans. Furthermore infections of the mucous membranes with fungi and mixed infections of the skin and the mucous membranes with said fungi and with bacteria, can successfully be treated with the compounds of the invention. The compounds may be administered in the form of solutions in lower alcohols (even as sprays), ointments, creams and powders which are locally applied to the skin. Suitable carrier materials for ointments and creams are, for example, usual galenic mixtures of polyglycols and vaseline; the powders preferably contain talcum as carrier material.

Depending on the degree of the infection, the skin ointments and creams contain the active ingredient in a concentration of from 0.25 to 1 percent, and the mucous membrane ointments in a concentration of from about 0.25 to 0.5 percent.

The following examples serve to illustrate the invention, but they are not intended to limit it thereto.

EXAMPLE 1 a. 3-isocyano-2-carbomethoxy-4-methylthiophene 9.9 g (0.1 mol) of phosgene were introduced at C, while stirring, into a solution of 19.9 g (0.1 mol) of 3-formylamino-2-carbomethoxy-4-methylthiophene (m. p. 132 134 C, prepared from 3- amino-2-carbomethoxy-4-methyl-thiophene (m. p. 84 85 C) and formic acid) in 600 ml of methylene chloride and 50 ml of triethylamine. Stirring was continued for 1 hour at this temperature. The resulting solution was shaken twice with water, the organic phase was dried with sodium sulfate and, after distillation of the solvent, the solid residue was recrystallized from methylcyclohexane. Melting point 107 108 C.

In analogous manner there were obtained:

b. from 3-formylamino-2-carbomethoxy-thiophene (melting point 92 93 C) the 3-isocyano-2-carbomethoxy-thiophene (melting point 65 66 C);

c. from 3-formylamino-4-methyl-thiophene (melting point 1 13 114 C), the 3-isocyano-4-methylthiophene (boiling point 98 100 C under a pressure of 45 mm mercury);

from 3-formylamino-2-carbethoxy-4-methylthiophene (melting point 88 89 C), the 3-isocyano-2-carbethoxy-4-methyl-thiophene (melting point 76- 77 C);

. from 3-formylamino-2-carbo-n-propoxy-4-methylthiophene (melting point 81 82 C), the 3-isocyano-2-carbo-n-propoxy-4-methyl-thiophene (boiling point 90 92 C 0.005 mmHg);

1'. from 3-formylamino-2-carbomethoxy-5-methylthiophene (melting point 104 105 C), the 3-isocyano-2-carbomethoxy-5methyl-thiophene (melting point 82 83 C);

from 3-formyla.mino-2-carbomethoxy-4,5-

dimethyl-thiophene (melting point 123 124 C),

the 3-isocyano-2-carbomethoxy-4,5-

dimethylthiophene (melting point 84 85 C);

h. from 3-formylarnino-2-carbomethoxy-4-ethyl-5- methylthiophene (melting point 116 117 C), the 3-isocyano-2-carbomethoxy-4-ethyl-5-methylthiophene (melting point 38 39 C);

i. from 3-formylamino-2-carbomethoxy-4,5-

tetramethylenethiophene (melting point 121 122 C), the 3-isocyano-2-carbomethoxy-4,5- tetramethylene-thiophene (melting point 72 73 k. from 3-formylamino-4-cyano-2-methyl-thiophene (melting point 122 123 C), the 3-isocyano-4- cyano-Z-methylthiophene (melting point 107 108 C); i

1. from 3-formylamino-4-carbomethoxy-2- methylthiophene (melting point 125 126 C), the 3-isocyano-4-carbomethoxy-2 methylthiophene (melting point 56 57 C);

m. from 3-formylamino-Z-carbomethoxy-S-phenylthiophene (melting point 1 12- 1 13 C), the 3-isocyano-2-carbomethoxy-5-phenyl-thiophene (melting point 125- 126 C);

n. from 3-formylamino-2-carbomethoxy-4-phenyl-5- methylthiophene (melting point 122 124 C), the 3-isocyano-2-carbomethoxy-4-phenyl-5- methyl-thiophene (melting point 105 107 C).

EXAMPLE 2 3-isocyano-2-carbomethoxy-4-methylthiophene 19.9 g (0.1 mol) of 3-formylamino-2-carbomethoxy- 4methyl-thiophene were mixed with 26.4 g of ptoluene-sulfochloride and the mixture was introduced into ml of pyridine under stirring. Within 20 minutes, an orange red solution formed which slowly turned dark green during 1 hour. The temperature rose to about 30 35 C. After 2 hours the solution was cooled and poured into 1 l of ice water. The mixture as extracted with ether, the ether solution was washed successively with 1N hydrochloric acid and twice with water, and finally dried with sodium sulfate. After evaporation of the ether the solid crude product was recrystallized from methylcyclohexane. Melting point 107-108 C.

The compounds mentioned in Example 1 were also prepared in a manner analogous to this Example 2.

EXAMPLE 3 3-isocyano-2-carbomethoxy-4-methyl-thiophene 10 g (0.05 mol) of 3-formylamino-2-carbomethoxy-4 -methyl-thiophene were dissolved in 15 ml of pyridine and 75 ml of chloroform. 4.6 g of phosphoroxy chloride were added dropwise while stirring at 0 10 C. Stirring was continued for 1 hour at room temperature and then the solution was poured in 150 ml of ice water. The organic phase was separated, washed two times each with cold 1N hydrochloric acid and a sodium bicarbonate solution, and dried with sodium sulfate. After evaporation of the solvent the residue was recrystallized from methylcyclohexane. Melting point: 107 108 C.

EXAMPLE 4 3-isocyano-4-methyl-thiophene 25 g of finely ground potassium hydroxide, which had been molten previously, and 75 ml of benzene were refluxed under stirring. A mixture of 11.3 g (0.1 mol) of 3-amino-4-methyl-thiophene and 25 ml of chloroform was added in such a manner that the exothermic reaction kept the mixture slightly boiling. When the reaction was complete the mixture was refluxed for another 15 minutes and cooled. The precipitate was filtered and washed with a small amount of benzene. The combined benzene phases were washed successively with 5 percent-hydrochloric acid, 10 percent-sodium carbonate solution and water. After evaporation of the benzene, 3.5 g of 3-isocyano- 4-methyl-thiophene were obtained; boiling point: 98 C/45 torr.

We claim:

1. Thiophene-3-isonitrile of the general formula 1 R1 NO Bil H-Rr s in which carbomethoxy and R and R together are tetramethylene.

4. The compound defined in claim 1 wherein R is carbomethoxy, R is methyl and R is methyl.

5. The compound defined in claim 1 wherein R is a carbomethoxy, R is phenyl and R is methyl. 

2. The compound defined in claim 1 wherein R1 is carbomethoxy, R2 is methyl and R3 is hydrogen.
 3. The compound defined in claim 1 wherein R1 is carbomethoxy and R2 and R3 together are tetramethylene.
 4. The compound defined in claim 1 wherein R1 is carbomethoxy, R2 is methyl and R3 is methyl.
 5. The compound defined in claim 1 wherein R1 is carbomethoxy, R2 is phenyl and R3 is methyl. 